Fix MISRA rule 8.4 Part 2

Rule 8.4: A compatible declaration shall be visible when
          an object or function with external linkage is defined

Fixed for:
	make DEBUG=1 PLAT=juno LOG_LEVEL=50 all

Change-Id: Ic8f611da734f356566e8208053296e6c62b54709
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>
diff --git a/plat/arm/css/common/css_topology.c b/plat/arm/css/common/css_topology.c
index 9b114e2..bccf2c8 100644
--- a/plat/arm/css/common/css_topology.c
+++ b/plat/arm/css/common/css_topology.c
@@ -1,10 +1,11 @@
 /*
- * Copyright (c) 2015-2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2018, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
 #include <plat_arm.h>
+#include <platform.h>
 
 #if ARM_PLAT_MT
 #pragma weak plat_arm_get_cpu_pe_count